Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651447
M. Fila, G. Taylor, J. Hiscock, M. Irving, P. Lang
Increasing penetration of Distributed Generation (DG) in distribution networks significantly changes both the real and reactive power flows in the network and can create serious voltage control problems. Furthermore, traditional Automatic Voltage Control (AVC) schemes that can normally deal with the reverse power flows, are unable to cope with the voltage problems associated with the presence of DG under certain conditions. Several techniques have been deployed to improve distribution network voltage profiles in such cases, for instance network reinforcement or active voltage control with remote voltage sensing units. Another method that has been proposed and recently implemented is the SuperTAPP n+ relay scheme that is based on locally taken measurements at the substation level combined with a state estimation technique. Such an approach enables assessment of the voltage rise at the point of connection of DG and effective control of the voltage level at the substation. The first objective of this paper is to present the fundamental principles of innovative voltage control schemes for distribution networks with DG based on locally measured signals. Secondly the functionality of the most flexible scheme will be demonstrated via software simulation for a range of distribution network case studies based upon realistic EDF Energy network scenarios. Finally, the results from the modelling and analysis of the SuperTAPP n+ relay scheme and its feasible application will be discussed and detailed conclusions are presented.
{"title":"Flexible voltage control to support Distributed Generation in distribution networks","authors":"M. Fila, G. Taylor, J. Hiscock, M. Irving, P. Lang","doi":"10.1109/UPEC.2008.4651447","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651447","url":null,"abstract":"Increasing penetration of Distributed Generation (DG) in distribution networks significantly changes both the real and reactive power flows in the network and can create serious voltage control problems. Furthermore, traditional Automatic Voltage Control (AVC) schemes that can normally deal with the reverse power flows, are unable to cope with the voltage problems associated with the presence of DG under certain conditions. Several techniques have been deployed to improve distribution network voltage profiles in such cases, for instance network reinforcement or active voltage control with remote voltage sensing units. Another method that has been proposed and recently implemented is the SuperTAPP n+ relay scheme that is based on locally taken measurements at the substation level combined with a state estimation technique. Such an approach enables assessment of the voltage rise at the point of connection of DG and effective control of the voltage level at the substation. The first objective of this paper is to present the fundamental principles of innovative voltage control schemes for distribution networks with DG based on locally measured signals. Secondly the functionality of the most flexible scheme will be demonstrated via software simulation for a range of distribution network case studies based upon realistic EDF Energy network scenarios. Finally, the results from the modelling and analysis of the SuperTAPP n+ relay scheme and its feasible application will be discussed and detailed conclusions are presented.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129874493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651540
G. Carpinelli, P. Caramia, P. Varilone, P. Verde
The voltage continuity and quality are two different aspects of the quality on the electrical supply. Their regulation is of great importance due to the economical consequences associated with the presence of the disturbances in the electrical power systems. While voltage continuity has been regulated in several countries for his undouble importance, the voltage quality has only recently become an important concern for utilities, customers and consulting engineers. Actually, a fervid international debate is underway to find the best economic regulatory mechanism to improve the voltage quality. This paper illustrates some mechanisms of economic voltage quality regulation proposed in the most recent international literature.
{"title":"On the economic regulation of voltage quality","authors":"G. Carpinelli, P. Caramia, P. Varilone, P. Verde","doi":"10.1109/UPEC.2008.4651540","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651540","url":null,"abstract":"The voltage continuity and quality are two different aspects of the quality on the electrical supply. Their regulation is of great importance due to the economical consequences associated with the presence of the disturbances in the electrical power systems. While voltage continuity has been regulated in several countries for his undouble importance, the voltage quality has only recently become an important concern for utilities, customers and consulting engineers. Actually, a fervid international debate is underway to find the best economic regulatory mechanism to improve the voltage quality. This paper illustrates some mechanisms of economic voltage quality regulation proposed in the most recent international literature.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130251774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651460
M. Aghamohammadi, M. Saeedi, M. Zare
Nowadays penetration level of distributed generation in type of small synchronous generators is considerable in power systems. Without accounting for uncertainty factor in dynamic parameters of small synchronous generators, stability assessment of these generators in wide-area power system is uncertain and time consuming by itself. So, regarding small generators in medium voltage level, stability assessment of bulk power systems should be carried out with some simplification accompanied acceptable tradeoff. This paper proposes two approaches for modeling the reduction of subtransmision network including small synchronous generator. The effect of the proposed reduction methods on the transient stability evaluation of bulk power system has been investigated. The proposed approaches have been demonstrated on two types of test system, IDRC 24-bus and Iran national test systems.
{"title":"Impacts of small synchronous generators at medium voltage on transient stability of bulk power system","authors":"M. Aghamohammadi, M. Saeedi, M. Zare","doi":"10.1109/UPEC.2008.4651460","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651460","url":null,"abstract":"Nowadays penetration level of distributed generation in type of small synchronous generators is considerable in power systems. Without accounting for uncertainty factor in dynamic parameters of small synchronous generators, stability assessment of these generators in wide-area power system is uncertain and time consuming by itself. So, regarding small generators in medium voltage level, stability assessment of bulk power systems should be carried out with some simplification accompanied acceptable tradeoff. This paper proposes two approaches for modeling the reduction of subtransmision network including small synchronous generator. The effect of the proposed reduction methods on the transient stability evaluation of bulk power system has been investigated. The proposed approaches have been demonstrated on two types of test system, IDRC 24-bus and Iran national test systems.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130594188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651672
O. Ahmed, J. Bleijs
This paper presents a new combined design of a passive series LC filter with a 3-phase diode bridge rectifier using three capacitors at the input of the bridge rectifier to boost the dc output voltage without the need for active switching devices. Therefore the rectifier can be use for machine drives without requiring machine de-rating or overmodulation techniques. The input inductor/capacitor filter works to reduce the harmonics current even if the applied ac voltage is already distorted, while the bridge capacitors improve the input power factor. This configuration minimizes the 5th and 7th current harmonics without increasing higher order harmonics, resulting in a total harmonic distortion of less than 2%. At medium and high power levels the rectifier operates at nearly unity power factor. In the paper a comparison is made between a number of three phase diode bridge rectifier topologies with passive networks, and it is shown that the new design outperforms other circuits in all aspects. The operation of the new three phase diode bridge rectifier topology is illustrated by simulation results, which are confirmed by experimental data.
{"title":"Three phase passive bridge rectifier with low distortion input current and boosted DC output voltage","authors":"O. Ahmed, J. Bleijs","doi":"10.1109/UPEC.2008.4651672","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651672","url":null,"abstract":"This paper presents a new combined design of a passive series LC filter with a 3-phase diode bridge rectifier using three capacitors at the input of the bridge rectifier to boost the dc output voltage without the need for active switching devices. Therefore the rectifier can be use for machine drives without requiring machine de-rating or overmodulation techniques. The input inductor/capacitor filter works to reduce the harmonics current even if the applied ac voltage is already distorted, while the bridge capacitors improve the input power factor. This configuration minimizes the 5th and 7th current harmonics without increasing higher order harmonics, resulting in a total harmonic distortion of less than 2%. At medium and high power levels the rectifier operates at nearly unity power factor. In the paper a comparison is made between a number of three phase diode bridge rectifier topologies with passive networks, and it is shown that the new design outperforms other circuits in all aspects. The operation of the new three phase diode bridge rectifier topology is illustrated by simulation results, which are confirmed by experimental data.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130885468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651666
C. Lam, F. Ng, M. Wong
In this paper, a control scheme for a novel capacitive-coupled STATCOM in three-phase power system is proposed and analyzed. In order to maintain the dc-link voltage to a constant level, an active block diagram model is built. Based on this model, a novel dc-link voltage feedback control scheme is proposed and discussed. The proposed novel capacitive-coupled STATCOM is characterized by lower the dc-link rating of the conventional inductive-coupled STATCOM with good system compensation feature. Simulation results are given to prove the effectiveness of the control scheme together with the dc-link voltage feedback control in the novel capacitive-coupled STATCOM.
{"title":"Control scheme of a novel capacitive-coupled STATCOM","authors":"C. Lam, F. Ng, M. Wong","doi":"10.1109/UPEC.2008.4651666","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651666","url":null,"abstract":"In this paper, a control scheme for a novel capacitive-coupled STATCOM in three-phase power system is proposed and analyzed. In order to maintain the dc-link voltage to a constant level, an active block diagram model is built. Based on this model, a novel dc-link voltage feedback control scheme is proposed and discussed. The proposed novel capacitive-coupled STATCOM is characterized by lower the dc-link rating of the conventional inductive-coupled STATCOM with good system compensation feature. Simulation results are given to prove the effectiveness of the control scheme together with the dc-link voltage feedback control in the novel capacitive-coupled STATCOM.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129889811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651522
R. Pereira, A.J.C. Pereira, C. Ferreira, F. Barbosa
Electric power network stability analysis requires that all system components are represented by their models. Usually, detailed data about system components such as generators, transformers and transmission lines are available. In this case accurate models can be derived from the network devices. However, corresponding data for individual loads are not always available, which makes the modelling of loads an important area of research studies. In this paper it is studied and analysed the effect of the composite load models in the dynamic voltage stability of an electric power network. The composite load models comprise residential, commercial and industrial loads. A severe contingency situation was simulated. The automatic voltage regulators of the generating units, the turbine speed governors, and the under load tap changers models were taken into account. The simulation results were obtained using the EUROSTAG software package. Finally, some conclusions that provide a better understanding of the dynamic voltage stability are pointed out.
{"title":"Dynamic voltage stability assessment of an electric power network using composite load models","authors":"R. Pereira, A.J.C. Pereira, C. Ferreira, F. Barbosa","doi":"10.1109/UPEC.2008.4651522","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651522","url":null,"abstract":"Electric power network stability analysis requires that all system components are represented by their models. Usually, detailed data about system components such as generators, transformers and transmission lines are available. In this case accurate models can be derived from the network devices. However, corresponding data for individual loads are not always available, which makes the modelling of loads an important area of research studies. In this paper it is studied and analysed the effect of the composite load models in the dynamic voltage stability of an electric power network. The composite load models comprise residential, commercial and industrial loads. A severe contingency situation was simulated. The automatic voltage regulators of the generating units, the turbine speed governors, and the under load tap changers models were taken into account. The simulation results were obtained using the EUROSTAG software package. Finally, some conclusions that provide a better understanding of the dynamic voltage stability are pointed out.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128906016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651433
S. Sekioka
This paper describes lightning surge propagation characteristics on a nonuniform line are dependent on location. The propagation characteristics of the nonuniform line are different from those of the uniform one due to multiple reflections on the nonuniform line. It is impossible to derive an analytical formula to represent the surge characteristics of the nonuniform line in time domain without assumption and approximation. This paper presents a method to obtain an approximate formula to represent the lightning surges along the nonuniform line using a lattice diagram method.
{"title":"Surge propagation characteristics on nonuniform lines","authors":"S. Sekioka","doi":"10.1109/UPEC.2008.4651433","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651433","url":null,"abstract":"This paper describes lightning surge propagation characteristics on a nonuniform line are dependent on location. The propagation characteristics of the nonuniform line are different from those of the uniform one due to multiple reflections on the nonuniform line. It is impossible to derive an analytical formula to represent the surge characteristics of the nonuniform line in time domain without assumption and approximation. This paper presents a method to obtain an approximate formula to represent the lightning surges along the nonuniform line using a lattice diagram method.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121132236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651479
Yang Yu, Z. Hao, Baohui Zhang, Bo Zhi-qian
The neutral point potential of the grounding transformer will be changed when HVDC system operates in a dc monopole ground return mode and dc bias may be generated. Dc bias will change exciting currentdasias waveform. Then large quantity of even and odd harmonics will be produced. The harmonics will do harm to the transformer and its protection. This paper uses PSCAD/EMTDC to create a simulation model. It emulates exciting current of a practical 750 kV single-phase transformer in variant cases under dc bias. It studies the distortion of exciting current, harmonic distribution, the peak value of the exciting current under dc bias. Meanwhile, the performance of transformer protection in this harmonic environment is analyzed. The loss made by exciting currentpsilas distortion and elevated temperature rise of core tie-plate are quantitative calculated.
{"title":"The effect research on transformers and protections under HVDC monopole ground operation mode","authors":"Yang Yu, Z. Hao, Baohui Zhang, Bo Zhi-qian","doi":"10.1109/UPEC.2008.4651479","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651479","url":null,"abstract":"The neutral point potential of the grounding transformer will be changed when HVDC system operates in a dc monopole ground return mode and dc bias may be generated. Dc bias will change exciting currentdasias waveform. Then large quantity of even and odd harmonics will be produced. The harmonics will do harm to the transformer and its protection. This paper uses PSCAD/EMTDC to create a simulation model. It emulates exciting current of a practical 750 kV single-phase transformer in variant cases under dc bias. It studies the distortion of exciting current, harmonic distribution, the peak value of the exciting current under dc bias. Meanwhile, the performance of transformer protection in this harmonic environment is analyzed. The loss made by exciting currentpsilas distortion and elevated temperature rise of core tie-plate are quantitative calculated.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122264285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651649
G. Zafarabadi, E. A. Boroujeni
In stand still frequency response, extrapolation in low frequency will be used to calculate Ld0 (initial value of d-axes inductance), Lq0 (initial value of q-axes inductance) and Ra (stator resistance).Because of dependency of generator parameters to this parameters, accuracy of these parameters for exact identification is so important. In this paper effect of stator resistance on generator parameters identification has investigated by sensitivity analysis and then this effect has shown on practical SSFR data of Shahid Rajaei powerplant which are used for parameters identification by pattern search method.
{"title":"Investigation of effect of stator resistance on accuracy of generator parameters identification with SSFR method","authors":"G. Zafarabadi, E. A. Boroujeni","doi":"10.1109/UPEC.2008.4651649","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651649","url":null,"abstract":"In stand still frequency response, extrapolation in low frequency will be used to calculate Ld0 (initial value of d-axes inductance), Lq0 (initial value of q-axes inductance) and Ra (stator resistance).Because of dependency of generator parameters to this parameters, accuracy of these parameters for exact identification is so important. In this paper effect of stator resistance on generator parameters identification has investigated by sensitivity analysis and then this effect has shown on practical SSFR data of Shahid Rajaei powerplant which are used for parameters identification by pattern search method.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125678246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651514
Shujie Sun, N. Tai, Zhinqian Bo
This paper presents a kind of algorithm, which can decouple the electrical quantities of quadruple-circuit transmission lines and get completely independent 12 sequence components of quadruple-circuit transmission lines on the same tower system. Based on the analysis of transformation matrix and the impedance matrix of 12 sequence components, the principle of ground impedance relay and the corresponding protection setting scheme are discussed. Through PSCAD / EMTDC simulation software, the power transmission system model with quadruple-circuit transmission lines on the same tower under the voltage of 500 kV are established. The correct operation of protection scheme has been verified with extensive simulation studies.
{"title":"The study of ground distance protection of 500kV quadruple-circuit transmission lines on the same tower","authors":"Shujie Sun, N. Tai, Zhinqian Bo","doi":"10.1109/UPEC.2008.4651514","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651514","url":null,"abstract":"This paper presents a kind of algorithm, which can decouple the electrical quantities of quadruple-circuit transmission lines and get completely independent 12 sequence components of quadruple-circuit transmission lines on the same tower system. Based on the analysis of transformation matrix and the impedance matrix of 12 sequence components, the principle of ground impedance relay and the corresponding protection setting scheme are discussed. Through PSCAD / EMTDC simulation software, the power transmission system model with quadruple-circuit transmission lines on the same tower under the voltage of 500 kV are established. The correct operation of protection scheme has been verified with extensive simulation studies.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124103837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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